This invention relates to stackable block structures, and more particularly to a new corner block unit and system for forming corners in a stackable block structure.
Constructing stackable block structures, such as retaining walls, with block units, such as masonry building block units, presents particular problems. This is especially true with respect to the formation of outside corners of the stackable wall structures.
One such problem includes the fact that many such block units have an outer surface which is intended to be the surface which is to be exposed to increase the aesthetic appearance of the wall. When turning a corner, it is undesirable to have non-outer surface portions of the block unit to be showing.
Additionally, it has been a problem when turning a corner in a stackable block structure to provide for sufficient strength and stability with respect to the corner. Many stackable block structure systems do not allow for lockable engagement between the courses of blocks to substantially reduce the amount of horizontal movement of the corner, or allow for substantial overlap and interlocking between corner block units and standard block units such that the corner is further stabilized. Also, many systems do not allow for lockably maintaining structural reinforcement means such as a geogrid reinforcement mat between the courses of blocks in a corner. Also, in many such systems, it is difficult to maintain a running half bond throughout the remainder of the wall after turning a corner.
Some block systems use a ridge, or lip, at the top front of the blocks to maintain the blocks stacked on top thereof in position. However, such structures do not prevent both backward and forward horizontal movement of the block units. Additionally, they do not allow for a gradual curve in the stackable structure because the ridge, or lip gets in the way. Due to the lip configuration, such corner blocks also mandate that the front of the upper block be setback from the blocks in the course below such that the blocks cannot be stacked directly on top of one another to form a substantially vertical portion of a wall. The ability to vertically stack portions of a wall is especially desirable, for instance, in portions of walls that surround a stairwell going through a main wall.